Mixing makes of 6DJ8 tubes in preamp, and how to ascertain best position.

Lowrider75

Well-Known Member
Dec 4, 2019
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Hmmm ... too bad about the manufacturer.

Did BJ say why he recommended two different brands of 6DJ8 when stock is all the same? That's kinda strange. Mullards and Mazda - that's something you'd do when you only have two of each left. Using one to compensate or counter balance for the other.

Four NOS '70's Amperex 6922 Orange Globes would have done the trick for not much dinero.

But, sounds like you're settled with what you have. Have fun rolling.
I've always used two different brands in a preamp designed with a follower. You get the flavour of both tubes. In this case the warmth and textures of a Mullard with the more neutral dynamic mazda.
 

spiritofmusic

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Jun 13, 2013
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Allowing the tubes to bed in a few more days before I experiment with position.

After the benefits of lower noise > greater resolution, and this new tonal sweetness revealing my previous tubes to be grey and gritty, I'm now picking up a real uptick in air, and greater layering to my sound.

My soundfield just feels like it's both expanded and is drawing me in. As a result instrumental ease and separation is way up...but not a forensic pinpointing of detail. More the kind of thing you hear in live music where instruments and voices are spacious and unstrained, but the integral relationship of every strand is holistically maintained.

I can "look" at individual elements more easily, but the whole still remains greater than sum of parts.

This is yet more proof that noise reduction has effectively been my quest...from eliminating the harshness and smear of my old room acoustics, to dropping the noise floor via my mains and Sablon power cords, now to quieter tubes.

I cannot recommend Brent highly enough, urge anyone needing tube advice or inspired choice of tubes to refer to him. He pretty much backed up Bazelio's original suggestion to mix these selfsame tubes.

www.audiotubes.com
 
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bazelio

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Sep 26, 2016
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Brian, proof is always in the pudding.
Tbh, I'm gonna just stick to these two combinations, and see what transpires.

Re not going Nat...well, I can't deny comms are poor w them. What I also can't deny is how good the sound is.

Good news is that my teething issues are behind me, and SQ is massively enhanced. I've now ordered some '80s NOS gold pin Voskhod Rockets 6N1P for my SE2SE monos, and if I can drag tube bias voltage info out of Nat, I'm seriously considering the Mayer Elrog 211 tubes.
I've always been pleasantly surprised by what I've heard from NAT in limited exposure. In particular their preamps, as someone who dislikes active preamps in general. Elrog 211s would be great to try. But the price is intense. Best be sure before diving in head first. Good luck!
 

spiritofmusic

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Jun 13, 2013
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Brian, the main issue is the lack of self-biasing w the Nats, and inability to easily find anyone in the UK to help.

I love my audio and trying to improve SQ...but not at the expense of a shot of 1000V!
 

Direct Drive

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Sep 16, 2020
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the main issue is the lack of self-biasing w the Nats, and inability to easily find anyone in the UK to help.

I love my audio and trying to improve SQ...but not at the expense of a shot of 1000V!
Is that on the pre or power, or both? I presume at 1000vdc the power.
I presume their are trim pots on the pcb?
Steady hands if measuring across ....but not impossible.
Pic would be helpful.
 

spiritofmusic

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Jun 13, 2013
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Gerard, I'm afraid I have no pics, and there's nothing online. Just the mV value.
There is an option for a cathode-based mod that would effectively make my Nats self-biasing, but the guy performing this is retiring.
 

Direct Drive

Well-Known Member
Sep 16, 2020
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Gerard, I'm afraid I have no pics, and there's nothing online. Just the mV value.
There is an option for a cathode-based mod that would effectively make my Nats self-biasing, but the guy performing this is retiring.
Marc
Should be difficult and a little probe gauge (keeps the MM probes in the correct place) can be made up. I used to have to do it on the input valves of the Beard P101. Output were easy.
So if you have the mV value and they say adjust the bias to a specific mV, there will be trim pots.
It's amazing what you can do with high voltage and a couple of crocodile clips..... ;-)



I know some one who could do the mod for you, I suspect without any difficulty. Only issue is he is North and in lockdown!
We can speak. Sure it can be sorted.
 

spiritofmusic

Well-Known Member
Jun 13, 2013
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Thanks Gerard. No rush, what will be will be. I would absolutely love to convert my Nat monos to self-biasing, the ability to stay NOS GE 211, or go Pvsane or Mayer Elrog would be a real boon.
 

christoph

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Dec 11, 2015
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Allowing the tubes to bed in a few more days before I experiment with position.

After the benefits of lower noise > greater resolution, and this new tonal sweetness revealing my previous tubes to be grey and gritty, I'm now picking up a real uptick in air, and greater layering to my sound.

My soundfield just feels like it's both expanded and is drawing me in. As a result instrumental ease and separation is way up...but not a forensic pinpointing of detail. More the kind of thing you hear in live music where instruments and voices are spacious and unstrained, but the integral relationship of every strand is holistically maintained.

I can "look" at individual elements more easily, but the whole still remains greater than sum of parts.

This is yet more proof that noise reduction has effectively been my quest...from eliminating the harshness and smear of my old room acoustics, to dropping the noise floor via my mains and Sablon power cords, now to quieter tubes.

I cannot recommend Brent highly enough, urge anyone needing tube advice or inspired choice of tubes to refer to him. He pretty much backed up Bazelio's original suggestion to mix these selfsame tubes.

www.audiotubes.com
Congrats :cool:
 

spiritofmusic

Well-Known Member
Jun 13, 2013
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Christoph, this is a major improvement borne of two main things.

One is that these four tubes are simply quieter, and we all know how deadly noise is. For my sins, my noise issues inherent to my amps had been getting worse, ironically as I was progressively reducing noise floor on my grid, via power cords, and via room acoustics. This culminated in my most recent Bocchino Sablon Elite pwr cords upgrades really demonstrating that my old tubes were not up to snuff.

Two, is that these tubes, and the mix of Mullards and Mazdas, are sensational in their own right, with air, tonal color density and sweetness, absolutely suiting my system and individual tastes. I've run 6DJ8 tubes in the past that were...bland, leading edge sharp, dynamic but gritty. These are the first ones that maintain dynamics, and reveal a real bloom in soundstage and tonality.

And after some great comparator demoes over the years where I'm fully aware of shortcomings in my sound, this tubes upgrade feels like a quantum leap move in the right direction for me to engage further with more acoustic music.
 
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christoph

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Dec 11, 2015
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The right tubes can be magical :cool:
 

Zero000

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Jul 28, 2014
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Noise is deadly you say Marc.

But you listen to vinyl.

Sir, you cannot be serious!
 

spiritofmusic

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Jun 13, 2013
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C'mon, feel the noize!

Justin, I love noise. Part of the natural world. The only music that has a dead silent backdrop is the music you hear when you're dead.

Have no issue w diamond coursing thru petrochemical industry by-product. But I have an issue with irregularities in valves amplified thru my spkrs.
 
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Zero000

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I just had to call you out. It was a mood thang LOL;)

Still, a fair point I feel.
 

spiritofmusic

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Jun 13, 2013
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Sure Justin. One regarded theory for why we vinylphiles love LP is a certain level of noise associated w the medium. I don't doubt this is true.

However tube noise feels like an imposition, not a comfort factor.

And tbh, maybe I really loved yr Apogees because of some inherent noise in those 211s you were running. I truly mean that.
 

Zero000

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Jul 28, 2014
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Those 211 amps are really quiet. A point noted when I took them round and plugged them into a hi-fi reviewer's An Es, which are more sensitive, obviously.

As I point of note I have never heard An Es sound so good. I was amazed and I wish you were there as a witness. They really do love power far more than people think it would appear.

Better than I have ever heard at any Audionote demo at any show including those using their best equipment.
 

spiritofmusic

Well-Known Member
Jun 13, 2013
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Well, I suspect mine are too...proved by fact that tube rush way less just by changing these preamp tubes.
 

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